[cpollock]

When I restored my 38-7, the wire was disconnected between the switch (part 29) and the volume control, and it works fine. In the spirit of restoration I hooked it up, but the noise it created when turning the dial was not pleasant, so I just left it disconnected. The switch is just a slider mounted on the tuning dial that shorts to a piece of copper, and there is enough roughness on the slier to create a lot of noise. So in my experience there is no harm in removing it. However, you should be able to open the switch by actuating the knob on the tuner, so it should be relatively easy to test without getting out the wire cutters.
Is your volume control okay? I ended up replacing mine with a ganged pair of 1M audio taper pots.
Also, this seems of no consequence, but your schematic is slightly different than mine in appearance. My speaker symbol is aligned with the top of the output transformer, while yours is below it. Everything else looks identical. I wonder why Philco would have two schematics? Mine came from AntiqueRadioSchematics.
Above you mentioned there was no HV voltage on 6J5G. Did that get resolved? Seems like that is the obvious problem.

Good luck! My grandkids were listening to mine all weekend on the local oldies station.
Clif